1. Microbiology and Infectious Disease
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The flagellar motor of Vibrio alginolyticus undergoes major structural remodeling during rotational switching

  1. Brittany L Carroll
  2. Tatsuro Nishikino
  3. Wangbiao Guo
  4. Shiwei Zhu
  5. Seiji Kojima
  6. Michio Homma
  7. Jun Liu  Is a corresponding author
  1. Yale University, United States
  2. Nagoya University, Japan
Research Article
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Cite this article as: eLife 2020;9:e61446 doi: 10.7554/eLife.61446

Abstract

The bacterial flagellar motor switches rotational directions between counterclockwise (CCW) and clockwise (CW) to direct the migration of the cell. The cytoplasmic ring (C-ring) of the motor, which is composed of FliG, FliM, and FliN, is known for controlling the rotational sense of the flagellum. However, the mechanism underlying rotational switching remains elusive. Here, we deployed cryo-electron tomography to visualize the C-ring in two rotational biased mutants in Vibrio alginolyticus. We determined the C-ring molecular architectures, providing novel insights into the mechanism of rotational switching. We report that the C-ring maintained 34-fold symmetry in both rotational senses and the protein composition remained constant. The two structures show FliG conformational changes elicit a large conformational rearrangement of the rotor complex that coincides with rotational switching of the flagellum. FliM and FliN form a stable spiral-shaped base of the C-ring, likely stabilizing the C-ring during the conformational remodeling.

Article and author information

Author details

  1. Brittany L Carroll

    Department of Microbial Pathogenesis, Yale University, West Haven, United States
    Competing interests
    The authors declare that no competing interests exist.
  2. Tatsuro Nishikino

    Division of Biological Science, Nagoya University, Furo-cho, Japan
    Competing interests
    The authors declare that no competing interests exist.
  3. Wangbiao Guo

    Department of Microbial Pathogenesis, Yale University, West Haven, United States
    Competing interests
    The authors declare that no competing interests exist.
  4. Shiwei Zhu

    Department of Microbial Pathogenesis, Yale University, West Haven, United States
    Competing interests
    The authors declare that no competing interests exist.
  5. Seiji Kojima

    Division of Biological Science, Nagoya University, Furo-cho, Japan
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-5582-8935
  6. Michio Homma

    Division of Biological Science, Nagoya University, Furo-cho, Japan
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-5371-001X
  7. Jun Liu

    Department of Microbial Pathogenesis, Yale University, West Haven, United States
    For correspondence
    jliu@yale.edu
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-3108-6735

Funding

Japan Society for the Promotion of Science (JP16H04774)

  • Seiji Kojima

Japan Society of Ultrasonics in Medicine (JP18K19293)

  • Seiji Kojima

National Institute of Allergy and Infectious Diseases (AI087946)

  • Jun Liu

National Institute of General Medical Sciences (GM107629)

  • Jun Liu

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Reviewing Editor

  1. Edward H Egelman, University of Virginia, United States

Publication history

  1. Received: July 26, 2020
  2. Accepted: September 4, 2020
  3. Accepted Manuscript published: September 7, 2020 (version 1)
  4. Version of Record published: September 21, 2020 (version 2)

Copyright

© 2020, Carroll et al.

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.

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